In-situ-fabricated novel fluorescent fiber sensor for ultrasensitive, online detection of tyrosinase

The ability to sensitively and timely detect tyrosinase (TYR) activity is vital in biology and clinical diagnostics. Here, we proposed an in situ-fabricated fluorescent fiber sensor for sensitive, online sensing TYR activity. The sensor was fabricated via a one-step in situ redox reaction, enabling direct synthesis of yellow-emissive silicon quantum dots (SiQDs) on a tapered optical fiber surface. This strategy effectively avoided the need for complex fluorescent material synthesis and complicated integration with optical fibers. This sensor featured convenient preparation, excellent optical properties, stability, portability, and reusability, with low autofluorescence interference from biological samples. By integrating TYR-triggered dopamine quinone formation with SiQDs fluorescence quenching, the sensor achieved ultra-sensitive and highly specific quantification of TYR activity, featuring a detection limit of 0.025 U/mL and a linear range from 0.03 to 1.0 U/mL. The sensor was effectively employed in real serum samples, confirming its practicality. The novel sensor delivers a straightforward, portable and sensitive solution for the online monitoring of TYR activity. This work provides a highly practical and efficient approach for fabricating fluorescent fiber sensors, advancing their clinical and biological applications.